The present invention is generally directed to bushing assemblies in vehicle suspension systems. More specifically, the present invention is directed to a unique construction of bushing assemblies used in vehicle suspension systems.
Vehicle suspension bushing assemblies are known. One such bushing assembly may be formed from a round inner metal bar pin that is an elongated piece of metal such as cast iron which is contained within a combination of a circular metal sleeve attached to an elastomeric material such as rubber. The circular metal sleeve and the round bar pin must be machined to very exact tolerances to properly fit together. The increased machining and processing of the components due to the required low tolerances increases costs. The circular bar pin may be heavy, which leads to increased material, manufacturing and shipping costs.
Another known bushing assembly may be formed from a round inner metal bar pin that is a machined length of metal such as aluminum that is bonded directly to an elastomeric material such as rubber. The direct bonding of the rubber to the inner metal bar pin requires specific types of metal and additional machining or processing to yield a proper bond between the inner metal and the rubber, thus increasing costs.
The combined inner metal bar pin bonded to a rubber bushing may also be inserted into a metal sleeve to form another known bushing assembly. The bushing assembly may have attachment means on both ends of the inner metal bar pin.
While prior vehicle suspension bushing assemblies have been adequate for certain purposes, they have lacked some of the advantages obtainable with the embodiments of the present invention. Many of these advantages are clearly described herein and others shall be readily apparent to those skilled in the art.
One advantage achieved by the present invention is the use of a deformable metal sleeve into which the metal bar pin is press fit.
Another advantage achieved by the present invention is by the use of low cost steel tube for the metal sleeve.
Another advantage achieved by the present invention is the use of an as-cast or near as-cast ductile inner metal bar pin that requires little or no machining or processing.
Another advantage achieved by the present invention is the lower costs achieved by the need for little or no machining of the inner metal bar pin.
Another advantage achieved by the present invention is the use of an inner metal bar pin with a non-circular cross section that has voids bounded by radially extending contact portions.
Another advantage achieved by the present invention is the lower cost of the reduced weight achieved by the use of an inner metal bar pin with a non-circular cross section with voids.
Another advantage achieved by the present invention is the lower cost of the reduced material required by the use of an inner metal bar pin with a non-circular cross section with voids.
Another advantage achieved by the present invention is the use of ductile cast iron for the metal bar pin.
Another advantage achieved by the present invention is the use of a process to insert the metal bar pin into the metal sleeve and rubber combination and to insert the resulting bushing assembly into a vehicle suspension component such as a torque rod in a single press fit operation.
Another advantage achieved by the present invention is by allowing the steel tube to deform into a non-circular shape during the press fit operation instead of requiring a precise tolerance to fit a uniform circular metal sleeve.
Another advantage achieved by the present invention is by controlling the amount of the steel tube deformation such that the bond line with the rubber component is not compromised.
Another advantage achieved by the present invention is designing a cruciform embodiment such that the press fit between the cruciform and the steel tube sleeve has two cruciform extension end surfaces in full contact with the steel tube and two cruciform extension end surfaces in only a line contact with the steel tube.
These and other advantages of the preferred forms of the invention will become apparent from the following description. It will be understood, however, that at apparatus could still appropriate the invention claimed herein without exhibiting each and every one of these advantages, including those gleaned from the following description. The appended claims, not any advantages recited or implied herein, define the subject matter of this invention. Any and all advantages are derived from the preferred forms of the invention, not necessarily the invention in general.